The Automatic Identification System (AIS) is a tracking system for identifying and locating marine vessels by electronically exchanging data with other nearby vessels, AIS base stations, and satellites. AIS information may be used in conjunction with marine radar to help avoid collision with other vessels. AIS transmissions include information such as vessel identifiers, position, course, and speed. AIS not only allows oncoming vessels to know each other's locations, but it also allows maritime authorities to track and monitor vessel movements as well. AIS devices utilize information from satellite positioning systems (e.g., GPS), as well as other electronic navigation sensors, and communicate the AIS data via a very high frequency (VHF) transceiver.
U.S. Pat. Pub. No. 2009/0161797 to Cowles et al. discloses a system for detecting and decoding Automatic Identification System (AIS) signals which includes a plurality of orbital satellites. Each orbital satellite has at least one antenna with at least one antenna polarization for receiving a radio frequency signal. Each orbital satellite also has a communication module for accepting the radio frequency signal, converting the radio frequency signal into sampled packetized data for insertion into a raw data stream, inserting a plurality of signal parameters into the raw data stream, and transmitting the raw data stream and a telemetry data stream to at least one ground station. A processor located at the ground station receives and processes the raw data stream to identify one or more candidate AIS message signals.
Despite the existence of such systems, further advancements in marine vessel monitoring may be desirable in certain applications.